1. Field of the Invention
The present invention relates to a high-voltage gas circuit breaker, and more particularly, to a gas circuit breaker for blowing an arc-extinguishing gas between a fixed arc contact and a movable arc contact to extinguish an arc during a circuit-breaking operation.
2. Description of the Related Art
Gas insulated switchgear or gas circuit breaker is an electrical device which is provided on an electrical line to safely block a current when switching the line by artificial means in a normal use state or when occurring a fault current such as ground fault or short circuit, thereby protecting a power system or power device. In this gas insulated switchgear, when the switchgear performs a trip operation an arc-extinguishing gas (for example, sulfur hexafluoride (SF6) gas) having an excellent insulation that has been compressed in a compression chamber is ejected to extinguish an arc occurring during the trip operation.
FIG. 1 is a cross-sectional view illustrating a structure of a circuit-breaking portion in a gas insulated switchgear in the related art, and FIG. 2 is a cross-sectional view illustrating an operation state of the circuit-breaking portion of FIG. 1.
As described above, a circuit-breaking portion in a gas insulated switchgear in the related art may include a fixed side and a movable side.
The fixed side is provided with a first fixed contact 1 and a fixed arc contact 2.
The movable side may include a second fixed contact 3, a movable contact 4 movably provided within the second fixed contact 3, a fixed piston 5 provided within the movable contact 4 to form a compression chamber 6, a movable arc contact 7 connected or separated to/from the fixed arc contact 2 while moving along with the movement of the movable contact 4, a nozzle 8 fixed to the movable contact, and a connecting rod 9 connecting a rod 10 of the movable contact 4 to an operating mechanism (not shown) of the switchgear.
In a conducting state of the switchgear, as illustrated in FIG. 1, the movable arc contact 7 is connected to the fixed arc contact 2, the line thereby maintaining a closed path.
When the switchgear being tripped in the foregoing state, a force is transferred to the connecting rod 9 connected to the operating mechanism in a right direction on the drawing (open path direction) to start a high-speed trip operation, and the movable contact 4 and movable arc contact 7 connected to the connecting rod 9 through the rod 10 are moved together in a moving direction of the connecting rod 9.
At this time, a volume of the compression chamber 6 formed by the movable contact 4 and the fixed piston 5 is drastically reduced according to a movement of the movable contact 4 and an arc is thereby generated between the movable arc contact 7 and the fixed arc contact 2 from a moment when the movable arc contact 7 is separated from the fixed arc contact 2 by a movement of the movable contact 4. When an arc is generated as described above, as illustrated in FIG. 2, a compression gas compressed within the compression chamber 6 is ejected in an arc direction through the nozzle 8, thereby extinguishing the arc and blocking the current.
On the other hand, there is a case that a dual motion method is applied thereto in order to increase the speed of separating the movable arc contact 7 and the fixed arc contact 2 and secure a sufficient insulation distance therebetween.
FIG. 3 a cross-sectional view illustrating a structure in which a dual motion method is applied to a gas insulated switchgear in the related art, and FIG. 4 is a cross-sectional view illustrating an operation state of FIG. 3.
As illustrated therein, in a gas circuit breaker with a dual motion method, an operating mechanism operates according to a trip signal and a force is transferred in a right direction on the drawing (open path direction), the nozzle 8, the movable arc contact 7, the movable contact 4, and the rod 10 are thereby moved in a right direction on the drawing, and at the same time, the fixed arc contact 2 is moved in a direction opposite to the moving direction of the movable side (left direction on the drawing) by a reverse link portion 11 connected to a front end of the nozzle 8.
In other words, when a nozzle-side link 12 connected to a front end of the nozzle 8 is moved in a right direction on the drawing, a rotating link 13 thereby rotates in a counterclockwise direction about a fixed pin 15 as a central axis.
As described above, according to the rotation of the rotating link 13, a fixed arc contact-side link 14 connected thereto is moved in a left direction on the drawing, and accordingly, the fixed arc contact 2 fixed to the fixed arc contact-side link 14 is also moved in a left direction on the drawing along with the fixed arc contact-side link.
In other words, in the foregoing structure, the fixed arc contact 2 is moved at the same speed in a direction opposite to the moving direction of the movable side using a moving force of the movable side, thereby multiplying the separation speed and securing a sufficient insulation distance.